Modified rotor blade assemblies with access windows and methods for making the same

ABSTRACT

Methods for modifying a rotor blade for a wind turbine include removing a cutout section from a shell of the rotor blade, wherein removing the cutout section provides an access window to an interior support section of the rotor blade, and sealing the cutout section back to the shell to close the access window.

BACKGROUND OF THE INVENTION

The subject matter disclosed herein relates to wind turbine rotor blades and, more specifically, to wind turbine rotor blades with access windows.

Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.

The construction of a modern rotor blade generally includes shell components and one or more internal structural components, such as spar caps and one or more shear webs. The shell, typically manufactured from layers of fiber composite and/or a lightweight core material, forms the exterior aerodynamic airfoil shape of the rotor blade. The spar caps provide increased rotor blade strength by integrating one or more structural elements running along the length of the rotor blade on both interior sides of the rotor blade. Shear webs are structural beam-like components running essentially perpendicular between the top and bottom spar caps and extending across the interior portion of the rotor blade between the outer shells. Spar caps have typically been constructed from glass fiber reinforced composites, though some larger blades may include spar caps constructed from carbon fiber reinforced composites.

The size, shape, and weight of rotor blades are factors that generally contribute to energy efficiencies of wind turbines. For example, an increase in rotor blade size can increase the energy production of a wind turbine. Thus, to ensure that wind power remains a viable energy power source, efforts have been made to increase energy outputs by increasing the length wind turbine blades. For instance, larger wind turbines may have rotor blades 70 meters in radius and larger.

However, it may become necessary to gain access to the interior of the rotor blade after it is manufactured or even installed. For example, operators may seek to gain access to the interior of the rotor blade at one or more locations to inspect, test and/or modify (e.g., repair) one or more interior portions of the rotor blade. While the shell may be partially removed to gain access to said interior, the repair and replacement of removing the shell may be labor and cost intensive.

Accordingly, alternative wind turbine rotor blades with access windows would be welcome in the art.

BRIEF DESCRIPTION OF THE INVENTION

In one embodiment, a method is disclosed for modifying a rotor blade for a wind turbine. The method includes removing a cutout section from a shell of the rotor blade, wherein removing the cutout section provides an access window to an interior support section of the rotor blade, and, sealing the cutout section back to the shell to close the access window.

In another embodiment, a modified rotor blade is disclosed for a wind turbine. The modified rotor blade includes an interior support section extending in a lengthwise direction, a shell surrounding the interior support section, and a cutout section sealed to the shell. The cutout section was previously temporarily removed from the shell to provide an access window to an interior of the rotor blade comprising the interior support section.

These and additional features provided by the embodiments discussed herein will be more fully understood in view of the following detailed description, in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the inventions defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

FIG. 1 is a perspective view of a wind turbine having one or more rotor blades that may incorporate an aerodynamic root adapter according to one or more embodiments shown or described herein;

FIG. 2 is a perspective view of a rotor blade of the wind turbine illustrated in FIG. 1 according to one or more embodiments shown or described herein;

FIG. 3 is a perspective view of a section of a rotor blade according to one or more embodiments shown or described herein;

FIG. 4 is a perspective view of a section of a rotor blade with a template on its exterior surface according to one or more embodiments shown or described herein;

FIG. 5 is a perspective view of a section of a rotor blade with a cutout section being removed from its shell according to one or more embodiments shown or described herein;

FIG. 6 is a perspective view of a section of a rotor blade with an access window according to one or more embodiments shown or described herein;

FIG. 7 is a perspective view of a section of a rotor blade with an access window having a support lip according to one or more embodiments shown or described herein;

FIG. 8 is a perspective view of a modified rotor blade having a cutout section resealed to its shell according to one or more embodiments shown or described herein;

FIG. 9 is a perspective view of a modified rotor blade having a cutout section resealed to its shell using a prefabricated sealing layer according to one or more embodiments shown or described herein; and,

FIG. 10 illustrates a method for modifying a rotor blade according to one or more embodiments shown or described herein.

DETAILED DESCRIPTION OF THE INVENTION

One or more specific embodiments of the present invention will be described below. In an effort to provide a concise description of these embodiments, all features of an actual implementation may not be described in the specification. It should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another. Moreover, it should be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking of design, fabrication, and manufacture for those of ordinary skill having the benefit of this disclosure.

When introducing elements of various embodiments of the present invention, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

Referring now to FIG. 1 a wind turbine 10 is illustrated. The wind turbine 10 includes a tower 12 with a nacelle 14 mounted thereon. A plurality of rotor blades 16 are mounted to a rotor hub 18, which is in turn connected to a main flange that turns a main rotor shaft. Depending on the configuration of the wind turbine 10, the plurality of rotor blades 16 can, for example, be mounted to the rotor hub 18 indirectly through a pitch bearing (not illustrated) or any other operable connection technique. The wind turbine power generation and control components are housed within the nacelle 14. The view of FIG. 1 is provided for illustrative purposes only to place the present invention in an exemplary field of use. It should be appreciated that the invention is not limited to any particular type of wind turbine configuration.

Referring now to FIG. 2, a perspective view of a rotor blade 16 is illustrated. The rotor blade 16 can include a root end 20 for mounting the rotor blade 16 to a mounting flange (not illustrated) of the wind turbine hub 18 (illustrated in FIG. 1) and a tip end 22 disposed opposite to the root end 20. The rotor blade 16 may comprise a pressure side 24 and a suction side 26 extending between a leading edge 28 and a trailing edge 30. In addition, the rotor blade 16 may include a span 32 defining the total length between the root end 20 and the tip end 22. The rotor blade 16 can further comprise a chord 34 defining the total length between the leading edge 28 and the trailing edge 30. It should be appreciated that the chord 34 may vary in length with respect to the span 32 as the rotor blade 16 extends from the root end 20 to the tip end 22.

The rotor blade 16 may define any suitable aerodynamic profile. Thus, in some embodiments, the rotor blade 16 may define an airfoil shaped cross-section. For example, the rotor blade 16 may also be aeroelastically tailored. Aeroelastic tailoring of the rotor blade 16 may entail bending the blade 16 in generally a chordwise direction x and/or in a generally spanwise direction z. As illustrated, the chordwise direction x generally corresponds to a direction parallel to the chord 34 defined between the leading edge 28 and the trailing edge 30 of the rotor blade 16. Additionally, the spanwise direction z generally corresponds to a direction parallel to the span 32 of the rotor blade 16. In some embodiments, aeroelastic tailoring of the rotor blade 16 may additionally or alternatively comprise twisting the rotor blade 16, such as by twisting the rotor blade 16 in generally the chordwise direction x and/or the spanwise direction z.

Referring now to FIGS. 3-9, the rotor blade 16 may be modified by having a cutout section 50 removed from the shell 40 of the rotor blade 16 to provide an access window 45. The access window 45 can provide access to an interior support section 60 of the rotor blade 16 such that modifications (e.g., bonding inspections, repair, or the like) may be performed thereon. The same cutout section 50 may subsequently be sealed back to the shell 40 to close the access window 45 and provide a closed rotor blade 16 ready for operation. By sealing the access window 45 using the same cutout section 50 removed for its creation, significant savings may be appreciated through greater efficiencies in required materials, labor and other relevant factors. Such modifications can be made when the rotor blade 16 is removed from the wind turbine 10, or potentially even up tower with the rotor blade 16 still attached.

Specifically, with particular reference to FIGS. 2 and 3, the rotor blade 16 may generally comprise an interior support section 60 extending in a spanwise direction z. The interior support section can comprise any structural support about the span length of the rotor blade 16. For example, in some embodiments, such as that illustrated in in FIGS. 3-9, the interior support section 60 may comprise a shear web 61 connected to at least one spar cap 62.

The interior support section 60 is surrounded by a shell 40 comprising an exterior surface 42 (i.e., the surface facing away from the rotor blade 16) and an interior surface 41 (i.e., the surface facing internal the rotor blade 16). The shell 40 may comprise any material or materials that form a contoured aerodynamic profile around the interior support section 60. For example, in some embodiments, the shell 40 can comprise one or more resin-infused fiber materials or other composites or fabrics suitable for an exterior of a rotor blade 16.

With particular reference to FIGS. 4 and 5, a cutout section 50 may be removed from the shell 40. The cutout section 50 may comprise any portion of shell 40 that provides access to the interior support section 60 and may be removed using any suitable method that allows the cutout section 50 to be sealed back to the shell 40 after the access window 45 is no longer needed.

For example, in some embodiments, such as that illustrated in FIG. 4, a template 55 may be temporarily disposed (e.g., resting or temporarily fixed using adhesive or the like) on the exterior surface 42 of the shell 40. The template 55 may allow for an operator to either mark the exterior surface 42 for subsequent cutting, or may even be held in place to guide the cutting itself. In embodiments where a plurality of cutout sections 50 are removed to form a plurality of access windows 45, a single template 55 may be used to individually mark/remove each cutout section 50, a plurality of templates 55 may be used to mark/remove each cutout section 50, or a single template 55 may be used to simultaneously mark/remove a plurality of cutout sections 50.

The cutout section 50 may then be removed (i.e., separated) from the shell 40 using any suitable technique such as cutting with blades, lasers or the like. It should be appreciated that the cutout section 50 should be removed from the shell 40 by a process that keeps at least a substantial portion of the cutout section 50 intact such that it may be reused with the rotor blade 16 after it is sealed back to the shell 40. In some particular embodiments, the cutout section 50 may be removed using a tapered angle, such as 10° or more, such that the cutout section may be subsequently disposed back in the access window 40 without falling there through.

The cutout section 50 may comprise a variety of shapes, sizes and configurations. For example, in some embodiments, such as that best illustrated in FIG. 5, the cutout section 50 may comprise an oblong shaped window extending in the spanwise direction z. In other embodiments, the cutout section 50 may comprise any other shape such as a circle, square, rectangle or any other geometrical or non-geometrical shape. Furthermore, the cutout section 50 may be sized to provide one or more operators visual and/or physical access to at least a portion of the interior support section 60. For example, the cutout section 50 may have a cross sectional area of 1 square meter or less, 2 square meters or less, 3 square meters or less or even greater than 3 square meters depending on its shape and location.

In some embodiments, the rotor blade 16 may have a single cutout section 50 removed therefrom. In other embodiments, the rotor blade 16 may have a plurality of cutout sections 50 removed therefrom. In such embodiments, the plurality of cutout section 50 may each be independently sized, shaped and positioned to provide access to the interior support section 60 as required. Such embodiments may depended on the spanwise length of the rotor blade 16 (e.g., longer rotor blades may have more cutout sections 50 removed therefrom) and/or the desired target access locations such as when particular inspection areas are known.

Still referring to FIG. 5, the cutout section 50 may be positioned at a place about the shell 40 such that it does not overlap with the spar cap 62. Such embodiments may help facilitate the removal of the cutout section 50 without encroaching on the interior support section 60 and still provide access for modification thereto. For example, in some embodiments, the cutout section 50 may be positioned between the spar cap 62 and the trailing edge 30 of the rotor blade 16. Such embodiments may help ensure no or minimal interference caused by removing portions of the interior support section 60 during removal of the cutout section 50 while still providing broad access for subsequent modifications. In some embodiments, the cutout section 50 may be positioned between the spar cap 62 and the leading edge 28 of the rotor blade 16.

With particular reference now to FIG. 6, an access window 45 may be provided as a result of the removal of the cutout section 50 as discussed above. The size, shape, configuration and position of the access window 45 can directly depend on the size, shape, configuration and position of the cutout section 50 removed from the shell 40.

The access window 45 can thereby provide an operator with access to one or more portions of the interior support section 60 of the rotor blade 16 such as for inspecting, testing and/or modifying the same. For example, in some embodiments, a bond 63 between the shear web 61 and a spar cap 62 may be modified (e.g., added, replaced or otherwise repaired). Such bonds 63 may be repaired using any suitable material or materials such as, for example, epoxies; urethanes, including polyurethane; cyclopentadienes, including dicyclopentadiene; methylmethacrylates; vinylesters; and/or polyesters.

The access window 45 comprises an outer perimeter 46 in the shell 40. In some embodiments, as discussed above, the cutout section 50 may be removed at an angle so that the perimeter 46 is tapered. For example, the perimeter 46 may be angled such that it generally funnels into the interior of the rotor blade 16. Such embodiments may facilitate support the cutout section 50 when it is disposed back in the access window 45 for sealing by preventing the cutout section 50 passing through the shell 40.

In some embodiments, one or more additional features may be connected to one or more portions of the perimeter 46 of the access window 45 for supporting the cutout section 50 when it is sealed back to the shell 40. For example, in some embodiments, such as that illustrated in FIG. 7, a support lip 47 may be connected to at least a portion of the perimeter 46 of the access window 45 such that the cutout section 50 may rest thereon during subsequent sealing. In some particular embodiments, the support lip 47 may be connected to the interior surface 41 of the shell 40 so as to specifically prevent the cutout section 50 passing through the access window 45 and into the interior of the shell 40. Such support lips 47 may comprise any suitable material and connection type to at least partially help support, guide or otherwise facilitate the sealing of the cutout section 50 back to the shell 40. For example, the support lip 47 may comprise an additional resin-infused fiber material bonded to the shell 40, or may comprise any other type of plate, tab, doubler or the like.

Referring now to FIG. 8, the cutout section 50 may subsequently be disposed back in the access window 45 (such as after one or more portions of the interior support section 60 are modified) so that it can be sealed back to the shell 40. The cutout section 50 may be disposed in the access window 45 using any type of permanent and/or temporary supports such as a support lip 47 as discussed herein or other clips, tabs, clamps or the like.

Once the cutout section 50 is disposed back in the access window 45, a joint 51 between the cutout section 50 and the shell 40 may be sealed. The joint 51 may be sealed using any suitable technique based on the material(s) of the cutout section 50 and the shell 40. For example, in some embodiments, the joint 51 may be sealed using one or more adhesives such as, for example, epoxies; urethanes, including polyurethane; cyclopentadienes, including dicyclopentadiene; methylmethacrylates; vinylesters; and/or polyesters.

Referring now to FIG. 9, in some particular embodiments, the sealing of the cutout section 50 to the shell 40 at the joint 51 may be facilitated through the utilization of one or more prefabricated sealing layers 53 disposed over the joint 51. The one or more prefabricated sealing layers 53 may comprise any material or materials that help seal space between the cutout section 50 and the shell 40 to provide a secure and fixed connection there between. For example, the one or more prefabricated sealing layers 53 may comprise a wire mesh, a resin-infused fiber material (such as one similar to or the same as the cutout section 50 and/or the shell 40), one or more biax fiberglass plies or the like.

The cutout section 50 may thus be sealed to the shell 40 at the joint using any suitable technique. In embodiments comprising the use of one or more adhesives or the like, sealing may comprise curing the seal using any suitable operation to reaffix the cutout section 50 to the shell 40. As a result, the rotor blade 16 may comprise a substantially uniform shell 40 incorporating the same cutout section 50 that was temporarily removed to provide access to the interior support section 60 via an access window 45. Reusing the cutout section 50 may provide a more efficient operation by avoiding a more substantial material buildup for the entire access window 45. Moreover, its position relative the rotor blade 16 may provide suitable access without interfering with one or more interior support structures (e.g., a spar cap 62).

Referring now to FIG. 10 (in addition to the exemplary structures illustrated in FIGS. 1-9), a method 100 is illustrated for modifying a rotor blade 16. The method 100 first comprises removing the cutout section 50 from the shell 40 of the rotor blade 16 in step 110. As discussed herein, removing the cutout section 50 from the shell 40 provides an access window 45 to the interior support section 60 of the rotor blade 16. In some embodiments, removing the cutout section in step 110 may optionally be preceded by temporarily disposing a template 55 on the shell 40 in step 105.

The method 100 further comprises sealing the cutout section 50 back to the shell 40 to close the access window 45 in step 120. The cutout section 50 may be disposed in the access window 45 and sealed back to the shell 40 using any suitable technique as disclosed herein. In some embodiments, the method 100 may be repeated to provide a plurality of access windows (sequentially, simultaneously, or combinations thereof) that are subsequently closed off using their respective cutout sections 50.

In some embodiments, the method 100 further comprises modifying at least one portion of the interior support section 60 of the rotor blade 16 via the access window 45 in step 115 while the cutout section 50 is removed from the shell 40 (i.e., after step 110 but before step 120). Such modification may comprise any internal adjustments as discussed herein such as modifying a bond 63 between a shear web 61 and a spar cap 62. In even some embodiments, the method 100 may further comprise connecting a support lip 47 to the shell 40 in step 116 prior to sealing the cutout section 50 back to the shell 40 in step 120.

It should now be appreciated that one or more cutout sections may be removed from the shell of a rotor blade to provide an access window providing access to an interior support section. The access window may be subsequently closed by sealing the same cutout section back to the shell without having to build up or replace missing material. Such methods and structures incorporating these techniques may thereby facilitate a more efficient inspection, testing and/or modification of an interior of a rotor blade.

While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims. 

What is claimed is:
 1. A method for modifying a rotor blade for a wind turbine, the method comprising: removing a cutout section from a shell of the rotor blade, wherein removing the cutout section provides an access window to an interior support section of the rotor blade; and, sealing the cutout section back to the shell to close the access window.
 2. The method of claim 1, further comprising modifying at least one portion of the interior support section of the rotor blade via the access window while the cutout section is removed from the shell.
 3. The method of claim 2, wherein modifying at least one portion comprises modifying a bond between a shear web and a spar cap.
 4. The method of claim 1, further comprising connecting a support lip to at least a portion of a perimeter of the access window for supporting the cutout section when it is sealed back to the shell.
 5. The method of claim 4, wherein the support lip is connected to an interior surface of the shell.
 6. The method of claim 1, wherein the cutout section removed from the shell does not overlap with a spar cap.
 7. The method of claim 6, wherein the access window is disposed between the spar cap and a trailing edge.
 8. The method of claim 1, further comprising temporarily disposing a template on an exterior surface of the shell to identify the cutout section to be removed.
 9. The method of claim 1, wherein sealing the cutout section back to the shell comprises disposing a prefabricated sealing layer over a joint between the cutout section and the shell.
 10. The method of claim 1, further comprising: removing at least one additional cutout section from the shell of the rotor blade, wherein removing each of the at least one additional cutout sections provides an additional access window to the interior support section of the rotor blade; and, sealing each of the at least one additional cutout sections back to the shell to close each of the additional access windows.
 11. The method of claim 10, further comprising modifying at least one additional portion of the interior support section of the rotor blade via each of the additional access windows while each of the additional cutout sections are removed from the shell.
 12. A modified rotor blade for a wind turbine, the modified rotor blade comprising: an interior support section extending in a spanwise direction; a shell surrounding the interior support section; and, a cutout section sealed to the shell, the cutout section being previously temporarily removed from the shell to provide an access window to the interior support section.
 13. The modified rotor blade of claim 12, further comprising a support lip connected to at least a portion of a perimeter of the access window for supporting the cutout section.
 14. The modified rotor blade of claim 13, wherein the support lip is connected to an interior surface of the shell.
 15. The modified rotor blade of claim 12, wherein the interior support section comprises a shear web connected to at least one spar cap.
 16. The modified rotor blade of claim 15, wherein the cutout section temporarily removed from the shell does not overlap with the at least one spar cap.
 17. The modified rotor blade of claim 12, wherein the cutout section is disposed between the at least one spar cap and a trailing edge.
 18. The modified rotor blade of claim 12, further comprising a prefabricated sealing layer disposed over a joint between the cutout section and the shell.
 19. The modified rotor blade of claim 12, wherein the shell and the cutout section comprise a resin-infused fiber material.
 20. The modified rotor blade of claim 12, wherein the shell comprises at least one additional cutout section sealed to the shell, wherein each of the at least one additional cutout sections was previously removed from the shell to provide at least one additional access window to an interior of the rotor blade. 